I can see Button being further off Hamiltons pace this year having to get used to the Kers while his team mate already ran it for a year. He will get used to it in testing but having a full year will be such an advantage when theres also the moveable wing to consider as well.
Surely it would have been better to introduce those items a year apart.
Actually think the Kers might effect/help button more, just because of his style of driving.
Why? Because Button's all about doing the same lap over and over, repeatable, he's not an overtaking demon, nor a speed king, he's rather dull. Hamilton is a speed king, he's all about overtaking, Kers will be for him, mostly about overtaking.
So Button will be finding the best spots on the lap to most effective improve his time every lap and using it consistantly while Hamilton is more likely to be up someones backside and using Kers to try to pass other cars, which often won't be at the best times for actual lap times.
We'll see though, it depends how overtaking is this year, kers and new back wings, and lots of other changes, and potentially utterly rubbish tires. Will everyone find it easier to overtake, or way way harder, or equally as ridiculous as last season, thats something to be seen. If Kers + back wing changes make slipstreaming less terrible and passing easier, then the advantage might swing back to Hamilton. If slipstreaming WITHOUT Kers is improved so Kers becomes better for overall lap time rather than a boost for overtaking, maybe it will benefit Button.
I don't think the actual fact of pressing a button for a little more speed is going to trouble Button because Hamilton has pressed a button with the Kers label on it more than Button
What we need to see from tires is, was it the first race last year, or a couple races in that had Button doing badly, Webber/Hamilton doing great, and they did an extra pitstop as their tires weren't great and they wanted to push on.
What they expected was everyones tires would degrade and everyone would stop, or at the least the new tires would offer a big enough speed advantage, over continually slowing older tires, to allow the pitstop to be worthwhile overall. Thats what we need, for that to have worked, where drivers have the option with 25 laps to go, to get new tires, in a 20 second pitstop, but be 2 seconds a lap faster for every remaining lap, and for passing to be hugely easier.
Last season the tires didn't degrade enough and new tires didn't offer enough advantage. A second pitstop needs to become a viable strategy, so some people try to hold track position with slower cars and other people try a new set and to burn back up to the front fast.